If you want to give your Pokemon more coverage, you could consider replacing one or two of, say, Samurott's water-type moves with something that can counter Electric-types or any of its other weaknesses in times of need. Surf is stronger, more accurate and more reliable than Aqua Tail, so you could think about it. Apply the same concept for all your other Pokemon and you should be up and running for your Pokemon League challenge. All the best! :)